Device for diffusing matter between two fluids via semi-permeable diaphragms

ABSTRACT

Apparatus for diffusing matter between two fluids is disclosed, including a stacked configuration of alternating spacing plates and pairs of semi-permeable membranes, the spacing plates including flow passages for each of the two fluids so that they can be passed between the pairs of semi-permeable membranes and between the spacing plates and the pairs of membranes, respectively, a first and second clamping plate, and means for clamping the first and second clamping plates together with the stacked configuration pressed between them. Specifically, in the improvement for this apparatus which is disclosed, the first clamping plate includes a pair of laterally extending side walls which form that clamping plate into cup-shaped configuration, and the apparatus also includes means for engaging the side walls of the first clamping plate to the second clamping plate at a plurality of locations around the periphery of the entire apparatus in order to contain the unit under increased pressure uniformly.

FIELD OF THE INVENTION

The present invention relates to apparatus for diffusing matter betweentwo fluids utilizing semi-permeable diaphragms or membrane which arearranged in pairs between spacing plates in a stacked configurationincluding at least two spacing plates and at least one pair ofdiaphragms. More particularly, the present invention relates to suchstacked configurations of spacing plates and pairs of semi-permeablemembranes wherein each plate comprises through flow passages for each ofthe respective fluids, these passages connected to the inlet and outlettherefore, so that one of the fluids can be led between the pairs ofdiaphragms and the other fluid can be led outside the diaphragms, thatis between the diaphragms and the spacing plates, and wherein the entirestacked configuration is clamped between a bottom portion and a topportion.

BACKGROUND OF THE INVENTION

The use of stacked configurations of alternating spacing plates andpairs of semi-permeable membranes for diffusing matter between twofluids has been known for many years. Such apparatus are thus disclosedin a number of patents, including Swedish Pat. Nos. 218,441 (U.S. Pat.No. 3,411,630), 301,029 (U.S. Pat. No. 3,501,011), 325,370 (U.S. Pat.No. 3,511,381), 314,167 (U.S. Pat. No. 3,516,548), and 342,144 (U.S.Pat. No. 3,734,298). In U.S. Pat. No. 3,734,298, for example, such adevice for use in dialysis is demonstrated. The device in this patentthus includes means for pressing the alternating spacer plates and pairsof membranes together between a pair of clamping plates utilizingclamping rails extending along and engaging grooves provided along thesides of both clamping plates. As shown in that patent, the clampingplates thus are provided at either end of the stacked configuration, anddo not extend laterally below any of the spacing plates and/or pairs ofmembranes, and the clamping rails shown therein (see FIG. 8) must thenbe attached by engaging the grooves on either end of the clampingplates. A problem in all of these constructions has been to provide apressure which is evenly distributed over the entire working surface, aswell as providing a suitable pressure in the areas around the throughflow passages in order to provide an adequate seal at those points. Ifthis is not obtained, there is a risk that an exterior leakage willoccur, and/or a leakage between the two fluids, which is entirelyunacceptable.

Reference can also be made to a number of other patents which attempt todemonstrate such diffusion apparatus which include alternating stacks ofspacing plates and pairs of semi-permeable membranes, each of whichsuffers from the deficiencies disclosed above. These include U.S. Pat.Nos. 3,494,469; 3,219,573; 3,051,316; and 3,219,572.

SUMMARY OF THE INVENTION

In accordance with the present invention, these and other problems havebeen solved in a simple and expedient manner. In particular, the priorapparatus for diffusing matter between two fluids which have employed aplurality of spacing plates, a plurality of pairs of semi-permeablemembranes, wherein the spacing plates include flow passages for each ofthese fluids so that when the spacing plates and the pairs ofsemi-permeable membranes are arranged in a stacked, alternatingconfiguration, one of the fluids may be passed between the pairs ofsemi-permeable membranes while the other fluid may be passed between thespacing plates and the pairs of semi-permeable membranes, a firstclamping plate, a second clamping plate, and means for clamping thefirst and second clamping plates together with the stacked configurationpressed therebetween, have now been substantially improved upon. Inparticular, in accordance with this invention, the first clamping plateincludes a pair of laterally extending side walls forming that clampingplate into a cup-shaped configuration, and means for engaging the sidewalls of the first clamping plate to the second clamping plate at aplurality of locations around the periphery of the apparatus areprovided, in order to contain the stacked configuration therebetweenwith increased pressure at those locations around the flow passages inthe spacing plates, again so that uniform pressure can be maintainedthroughout the entire working surface of the spacing plates, includingat those locations.

In a preferred embodiment to the present invention, the laterallyextending side walls of the first clamping plate extend for at leastone-half of the lateral surface area of the stacked configuration ofspacing plates and alternating pairs of semi-permeable membranes.

In another embodiment of the present invention, both the first andsecond clamping plates include laterally extending side walls, so thatboth the first and second clamping plates have a cup-shapedconfiguration. Preferably, both of the first and second clamping platesinclude means integral with their side walls so that they may engageeach other around the periphery of the apparatus.

In another embodiment of the present invention, locking means areprovided in the case where both the first and second clamping platesinclude laterally extending side walls, to permit the engagement ofthese two clamping plates together to provide the increased pressuredescribed above.

In a highly preferred embodiment of the present invention, where boththe first and second clamping plates include laterally extending sidewalls, they are provided with hook-shaped locking members integral withthe side walls so that the first clamping plate can telescopically gripthe second clamping plate at these locking members. Preferably, thehook-shaped locking members associated with the first clamping platewill include an outer flange extending substantially around the entireperiphery of that portion, while the hook-shaped locking meansassociated with the second clamping plate will include a plurality ofhook means again substantially around the entire periphery of the secondclamping plate, and including a plurality of apertures on the uppersurface thereof to assist in the manufacture of these clamping plates.

In yet another highly preferred embodiment of the present invention, theoverall apparatus will include an essentially rectangular shapeincluding tapering ends, and the flow passages will be associated withthe tapering ends, preferably so that the distance from each of the flowpassages to the laterally-extending side walls will be substantiallyreduced as compared to a purely rectangular configuration.

In yet another embodiment of the present invention, both the laterallyprojecting side walls of the first and second clamping plates include aplurality of individual flanges so that extremely high pressures can bedeveloped within the apparatus. In this manner a larger number ofindividual connections are maintained around the entire periphery of theapparatus.

In particular, the apparatus of the present invention can be utilizedfor purifying blood, that is as a so-called artificial kidney. Personsskilled in this art will realize, however, that the constructiondisclosed in this application may be used for many other purposes. Forinstance, it can be utilized in order to oxygenate blood. In that case,one of the above-mentioned fluids will be blood, whereas the other fluidwill consist of oxygen or a oxygen mixture. Alternatively, the device ofthis invention can be used for transferring matter from one gas toanother. It is therefore apparent that by "fluid" is meant both gasesand liquids in this application. However, as the device according tothis invention is primarily intended for purifying blood, it will bedescribed in the following detailed description in connection with sucha use.

The invention will be described in more detail in the following detaileddescription, with particular reference to the accompanying drawingswhich show as examples three preferred embodiments of the apparatus inaccordance with the present invention. All of these embodiments are thusmeant to be utilized in the first instance as artificial kidneys.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a top perspective view of the top clamping plate of anartificial kidney in accordance with the present invention.

FIG. 2 shows a side, partially sectional, perspective view of theartificial kidney of FIG. 1.

FIG. 3 shows a side, sectional view of the artificial kidney of FIG. 2,taken along section A--A of FIG. 2.

FIG. 4 shows a side, sectional view of the artificial kidney of FIG. 2,taken along Section B--B of FIG. 2.

FIG. 5 shows a top, perspective view of the clamping plate of anotherartificial kidney in accordance with the present invention.

FIG. 6 shows a side, partially sectional, perspective view of theartificial kidney shown in FIG. 5.

FIG. 7 shows a side, sectional view of the artificial kidney of FIG. 6taken along section A--A of FIG. 6.

FIG. 8 shows a side, sectional perspective view of the artificial kidneyof FIG. 6 taken along section B--B of FIG. 6.

FIG. 9 shows a bottom, perspective view of the bottom clamping plate ofthe artificial kidney of FIG. 5.

FIG. 10 shows a top, perspective view of the top clamping plate ofanother artificial kidney in accordance with the present invention.

FIG. 11 shows a side, partially sectional, perspective view of theartificial kidney of FIG. 10.

FIG. 12 shows a side, sectional view of the artificial kidney of FIG.11, taken along section A--A of FIG. 11; and

FIG. 13 shows a side, sectional view of the artificial kidney of FIG. 11taken along section B--B of FIG. 11.

DETAILED DESCRIPTION

The preferred embodiments of the present invention will now be reviewedin more detail with reference to these figures, in which like numeralsrefer to like portions thereof. The artificial kidney shown in FIGS. 1through 4 includes a top portion or clamping plate 1 and a bottomportion or clamping plate 2, as well as an intermediate package orstacked configuration of spacing plates 3 therebetween. Between eachpair of adjacent spacing plates 3, are provided a pair of diaphragms orsemi-permeable membranes 4. In FIGS. 2 through 4 these pairs ofdiaphragms are represented by the intersecting line between the spacingplates 3 shown therein, in order that the separate figures will not haveto be unnecessarily enlarged and detailed. In this example, both the topclamping plate and the bottom clamping plate are cup-shaped, that isinclude laterally extending side walls 7 and 8, respectively, and arebuilt from a framework of flanges 5 and 6, respectively. The laterallyextending side walls 7 and 8 preferably extend laterally for a distanceof at least half of the area of the stacked configuration of alternatingspacing plates and pairs of diaphragms. As can best be seen in FIGS. 3and 4, the top and bottom clamping plates are held together byhook-shaped locking members 9 and 10. Thus, in connection with thebottom clamping plate 2, its laterally extending side wall 8 includes anexterior flange running continuously essentially around the entireperiphery of the bottom clamping plate 2 forming hook-shaped lockingmember 9 thereabout. The top clamping plate 1, however, includes aplurality of separate hooks 10, as shown in FIG. 3, mounted so as toface inwardly, and adapted to engage flange 9, which extends outwardlyfrom its laterally extending side wall 8. Thus, while the laterallyextending side wall 7 of the upper clamping plate 1 extendssubstantially continuously around the entire periphery of the topclamping plate 1, it includes a plurality of hook members 10 extendingperiodically inwardly from side wall 7. Opposite each hook member 10thus provided on the upper clamping plate 1 an aperture 11 is provided.This permits the top clamping member 1 to be manufactured by extrusionprocesses in a simple extrusion tool divided into two parts, and beingmade without movable cores.

The blood may then be admitted through inlet opening 12 in the topclamping plate 1, while the purifying liquid is admitted through opening13 in top clamping plate 1. The method for achieving this result may bemore fully understood in connection with the patents mentioned above,including U.S. Pat. Nos. 3,411,630 and 3,734,298, those portions ofwhich are therefore incorporated herein by reference thereto. In asimilar manner, the blood and the purifying liquid are removed throughopenings 14 and 15 in the lower clamping plate 2, respectively. Finally,an aperture 16 in the top clamping plate 1 is provided to facilitatemounting of the artificial kidney of this invention, and this apertureis in turn plugged with the aid of a plug (not shown) and a gasket 17.

When this artificial kidney as shown in FIGS. 1 through 4 is finallyassembled, it is, as noted above, essential that an even pressure beapplied around the entire periphery of the kidney, and over the entireactive surface, as well as around openings 12, 13, 14 and 15,respectively. If this does not occur, there may be leaks either from thekidney itself, or between the blood and the purifying liquid therein.Practical tests and experiments have demonstrated that the hook-shapedlocking members can provide this desired pressure with the desired evendistribution of pressure throughout. This pressure distribution isfurther improved as a result of the tapering shape of the kidney asshown in FIG. 1. In this manner, this shape provides a small distancebetween openings 12 through 15 and each of the nearest locking membersto these openings are compared to that distance as it would occur if thekidney itself were strictly rectangular in configuration, as has beenthe case in the past.

Referring now to FIGS. 5 through 9, another embodiment of the artificialkidney of the present invention is shown therein. The overallconfiguration of this apparatus thus corresponds, at least in principal,with that of FIGS. 1 through 4. Consequently, the same numerals havebeen utilized, although a ' is employed in connection with each numeralin this embodiment. One primary difference with this embodiment lies inthe top clamping plate 1'. That is, in this case, the top clamping plate1' is shaped as a plate, that is it does not include any laterallyextending side walls. The top clamping 1' thus includes a plurality ofhook-shaped locking members 10' extending outwardly therefrom atlocations substantially around the entire periphery thereof. The bottomclamping plate 2' thus includes laterally extending side wall 8', and aplurality of apertures 11' corresponding with the locking members 10' onthe upper clamping plate 1', and adapted to engage these hook shapedlocking members 10'. Thus, the bottom clamping plate 2' is cupshaped andhas an upper flaring marginal portion 8a'. Again, the construction andfunction of the kidney itself is essentially the same as that of theembodiment shown in FIGS. 1 through 4. It should finally be noted thatthe top clamping plate 1' includes an upwardly laterally extending wall7', which again does not extend downwardly laterally with respect to thestacked configuration of spacing plates 3 and pairs of semi-permeablemembranes 4.

The embodiment shown in FIGS. 10 through 13 is again essentially thesame as that shown in FIGS. 1 through 4. The same reference numeralshave therefore again been utilized, although the addition of a " isemployed in this case. Again, the essential difference in thisembodiment lies in the locking members 9" and 10". In this embodiment,both the laterally depending side walls 7" and 8" of the top clampingplate 1" and bottom clamping plate 2", respectively, include a pluralityof hooks, comprising inversely U-shaped hook members 10" and 9",respectively, which may be aligned with each other in the manner shownin FIGS. 12 and 13. As a result, they form a groove, so that railmembers 20" may be inserted in that groove to lock the top and bottomclamping portions together. In all other respects, this construction isessentially the same as the constructions described above with respectto FIGS. 1 through 4, and therefore it is not necessary to describe theadditional individual details of this embodiment.

The present invention is, of course, not limited to the threeembodiments described above, but may be varied within the scope of thefollowing claims. Thus, the shape of the details forming part of theconstruction may be varied essentially without exceeding the scope ofthis invention.

What is claimed is:
 1. In an apparatus for diffusing matter between twofluids comprising a plurality of spacing plates, a plurality of pairs ofsemi-permeable membranes, said spacing plates including flow passagesfor each of said fluids, so that when said spacing plates and said pairsof semi-permeable membranes are arranged in a stacked configuration, oneof said fluids may be passed between said pairs of semi-permeablemembranes and said other fluid may be passed between said spacing platesand said pairs of semi-permeable membranes, a first clamping plate, asecond clamping plate, and means for clamping said first clamping plateto said second clamping plate with said stacked configuration pressedtherebetween, the improvement which comprises said first and secondclamping plates being substantially rectangular in configuration andincluding tapered end portions, said first clamping plate including apair of laterally extending side walls forming said first clamping plateinto a substantially cup-shaped configuration, said flow passages beingprovided at said tapered end portions of said first and second clampingplates so that the distance from said flow passages to said laterallyextending side walls is substantially reduced, and including means forengaging said side walls of said first clamping plate to said secondclamping plate at a plurality of locations substantially around theentire periphery of said apparatus, including said tapered end portions,in order to contain said stacked configuration under increased pressuretherebetween, said laterally extending side walls of said first clampingplate corresponding to greater than one-half of the lateral surface areaof said stacked configuration, so that said first clamping plate can betightly engaged with said second clamping plate without the need toemploy any additional clamping means therewith.
 2. The apparatus ofclaim 1 wherein said second clamping plate includes a pair of laterallyextending side walls forming said second clamping plate into asubstantially cup-shaped configuration.
 3. The apparatus of claim 2including means for engaging said side walls of said second clampingplate to said first clamping plate, and wherein both said means forengaging said side walls of said first clamping plate and said means forengaging said side walls of said second clamping plate are integral withsaid laterally extending side walls of said first clamping plate andsaid second clamping plate.
 4. The apparatus of claim 1 wherein saidsecond clamping plate is substantially planar, and includes a pluralityof outwardly extending locking members, and said means for engaging saidside walls of said first clamping plate to said second clamping platecomprises a plurality of apertures in said laterally extending sidewalls of said first clamping plate, said apertures corresponding to saidlocking members on said second clamping plate.
 5. In an apparatus fordiffusing matter between two fluids comprising a plurality of spacingplates, a plurality of pairs of semi-permeable membranes, said spacingplates including flow passages for each of said fluids, so that whensaid spacing plates and said pairs of semi-permeable membranes arearranged in a stacked configuration, one of said fluids may be passedbetween said pairs of semi-permeable membranes and said other fluid maybe passed between said spacing plates and said pairs of semi-permeablemembranes, a first clamping plate, a second clamping plate, and meansfor clamping said first clamping plate to said second clamping platewith said stacked configuration pressed therebetween, the improvementwhich comprises said first and second clamping plates each including apair of laterally extending side walls, said laterally extending sidewalls of said first clamping plate including at least a portiondisplaced outwardly from said laterally extending side walls of saidsecond clamping plate so that said second clamping plate is disposedwithin said portion of said first clamping plate.
 6. The apparatus ofclaim 5 wherein said laterally extending side walls of said firstclamping plate correspond to greater than about one half of the lateralsurface area of said stacked configuration.
 7. The apparatus of claim 5wherein said laterally extending side walls of said second clampingplate correspond to greater than about one half of the lateral surfacearea of said stakced configuration.
 8. The apparatus of claim 5 whereinsaid laterally extending side walls of both said first and secondclamping plates correspond to greater than about one half of the lateralsurface area of said stacked configuration
 9. The apparatus of claim 5including means for engaging said side walls of said first clampingplate to said second clamping plate at a plurality of locations aroundthe periphery of said apparatus in order to contain said stackedconfiguration under increased pressure therebetween, and means forengaging said side walls of said second clamping plate to said firstclamping plate, wherein both said means for engaging said side walls ofsaid first clamping plate and said means for engaging said side walls ofsaid second clamping plate are integral with said laterally extendingsaide walls of said first and second clamping plates, respectively. 10.The apparatus of claim 9 wherein said means for engaging said side wallsof said first clamping plate to said second clamping plate comprises aplurality of hook-shaped locking members projecting inwardly from saidlaterally projecting side walls of said first clamping plate, andwherein said means for engaging said side walls of said second plate tosaid first clamping plate comprise a substantially continuoushook-shaped flange member extending outwardly from said side walls ofsaid second clamping plate.
 11. The apparatus of claim 9 wherein saidsecond clamping plate includes a plurality of outwardly extendinglocking members, and said means for engaging said side walls of saidfirst clamping plate to said second clamping plate comprises a pluralityof apertures in said laterally extending side walls of said firstclamping plate, said apertures corresponding to said locking members onsaid second clamping plate.